1. Field of the Invention
This invention relates generally to skylight construction and more particularly is directed towards a new and improved sealing arrangement for skylights to maintain a weather-tight joint between a skylight and a roof having different co-efficients of thermal expansion.
2. Description of the Prior Art
Skylights built into the roofs of buildings have been in use for many years and serve to illuminate as well as to ventilate, when open, the interiors of buildings. In general, there is no great difficulty in installing a wooden framed skylight onto a wooden building or even onto a metal building where the skylight is small and conventional roofing sealing techniques may be used to advantage. However, considerable difficulties have been encountered where the skylight is relatively large and is fabricated from a material having a different co-efficient of thermal expansion from that of the roof to which it is installed. For example, skylights having aluminum frames have been installed on the roofs of steel buildings, but the result heretofore have been unsatisfactory. It has been found that installations of this type are extremely difficult to seal properly for any extended period of time. The aluminum frames of such skylights expand and contract under changing ambient temperatures at a rate different from the steel roof to which it is mounted. The condition causes relative movement between the skylight and the roof frequently resulting in the formation of leaks between the roof and the skylight. Various measures have been attempted to correct this problem but the results heretofore have not been effective, especially over the long term.
Accordingly, it is an object of the present invention to provide improved means for installing skylights in a manner to prevent leakage over a wide range of ambient temperatures. Another object of this invention is to provide improved sealing systems for use with a skylight fabricated from a material having a co-efficient of thermal expansion different from that of the roof to which it is mounted.